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Emerging OTEC Technology Could Generate Waves of Business Opportunities for Titanium

Leaders of the titanium industry would be well advised to track nascent developments in a renewable energy technology known as Ocean Thermal Energy Conversion (OTEC), which harnesses the solar energy absorbed by the oceans to generate electric power. According to information posted by various sources, the underlying concepts for OTEC have been under review for at least five decades. In recent years, several development projects have been announced to demonstrate the technology’s feasibility and generate energy.

Information posted online by the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy, offered a basic description of the technology, saying that OTEC uses the ocean’s warm surface water with a temperature of around 25°C (77°F) to vaporize a working fluid, which has a low-boiling point, such as liquefied ammonia. The vapor expands and spins a turbine coupled to a generator to produce electricity. The vapor is then cooled by seawater that has been pumped from the deeper ocean layer, where the temperature is about 5°C (41°F). That condenses the working fluid back into a liquid, so it can be reused, creating a continuous electricity generating cycle. The efficiency of the cycle is determined by the temperature differential; the bigger the temperature difference, the higher the efficiency. The technology is viable primarily in equatorial areas where the year-round temperature differential is at least 20°C or 36°F.

The U.S. Department of Energy offered several caveats when considering the technology, saying that OTEC power plants require substantial up-front capital investment upfront. “Private investors most likely would be unwilling to make the enormous initial investment required to build large-scale plants until the price of fossil fuels increases dramatically or national governments provide financial incentives. Another factor hindering the commercialization of OTEC is that there are only a few hundred land-based sites in the tropics where deep-ocean water is close enough to shore to make OTEC plants feasible.”

In addition, the Department of Energy indicated OTEC works best when the temperature difference between the warmer, top layer of the ocean and the colder, deep ocean water is about 36°F (20°C). “These conditions exist in tropical coastal areas, roughly between the Tropic of Capricorn and the Tropic of Cancer. To bring the cold water to the surface, ocean thermal energy conversion plants require an expensive, large-diameter intake pipe, which is submerged a mile or more into the ocean’s depths.”

A 2013 presentation by World Market Intelligence of London, titled “OTEC—Ocean Thermal Energy Conversion, Oahu, Construction Project Profile,” described an OTEC project in West Oahu, Hawaii—a $400-million project that involves the construction of a 100 MW off-shore power generation hub. Components of the OTEC system include a floating platform; power transmission lines; transformers, pumping motors and turbines, along with related infrastructure. The system will be located five miles (eight kilometers) offshore of Kahe Point in West Oahu. The World Market Intelligence report indicated OTEC International LLC is currently working with Hawaiian Electric Co. on a 25-year power-purchase agreement. The project has a target operational date of 2018.

Separately, Lockheed Martin, Bethesda, MD, is working with Hong Kong-based Reignwood Group to develop an OTEC pilot power plant off the coast of southern China. A press release from Lockheed Martin stated that a memorandum of agreement between the two companies was signed two years ago in Beijing. A spokeswoman from Lockheed Martin said detailed design, pre-construction and permitting activities are targeted to start this year, with construction activities occurring in 2016-2017.

According to the press release, as well as other online sources, a 10-megawatt offshore plant, to be designed by Lockheed Martin, will be supply 100 percent of the power needed for a green resort to be built by Reignwood Group. In addition, the agreement could lay the foundation for the development of several additional OTEC power plants ranging in size from 10 to 100 megawatts, for a potential multi-billion dollar value.

Unlike other, more familiar renewable energy technologies such as solar and wind, Lockheed Martin said power from an OTEC system is “base load,” meaning it can be produced consistently 24 hours a day, 365 days a year. A commercial-scale OTEC plant will have the capability to power a small city. The energy can also be used for the cultivation of other crucial resources such as clean drinking water and hydrogen for applications such as electric vehicles.

Once the proposed plant is developed and operational, the two companies plan to use the knowledge gained to improve the design of the additional commercial-scale plants, to be built over the next 10 years. Each 100-megawatt OTEC facility could produce the same amount of energy in a year as 1.3 million barrels of oil.

What is the significance of the Lockheed Martin and West Oahu projects for the titanium industry? While there are unanswered questions regarding the operational feasibility, economic viability and long-range potential of OTEC technology, the initial interest for the titanium industry to explore this technology is the most-obvious factor: this is an energy system that operates in ocean waters. Given titanium’s corrosion-resistance properties to salt water, as well as its light weight and superior mechanical properties, titanium would be a strong contender for various OTEC components and systems. Titanium could capitalize on its demonstrated performance as a material of choice for industrial applications such as desalination plants and heat exchangers.

A presentation by OTEC International LLC to the World Bank, spelled out “under the hood” components and systems for the technology, a bullet-point list that included heat exchangers, turbines, pumps, valves, motors and variable-frequency drives, pipes, tubing, platforms and moorings. Some or all of those items represent possible application areas for titanium. The OTEC International presentation suggested OTEC is one of several renewable, green energy technologies, along with wind, solar, geothermal, biomass, hydropower—that could serve as “a catalyst for economic growth. No single technology provides an ideal solution.”

Albert Bruneau, executive vice president of Vallourec Heat Exchanger Tubes, as subsidiary of Vallourec SA, Boulogne-Billancourt, Paris, France, during a presentation at TITANIUM EUROPE 2015 Conference and Exposition in Sorrento, Italy, made mention of OTEC as a potential new market to be explored by the titanium industry.

Bruneau lamented that capital intensive projects that require titanium, such as OTEC or desalination facilities, often are subject to cancellations or postponements, while financial pressures and shifting economic conditions also create significant variables. While there is considerable risk regarding leading-edge power generating technologies, such as OTEC, Bruneau shared his thoughts on how the titanium industry should address market uncertainty in the coming years. He suggested a pro-active, aggressive approach to tout the benefits of titanium.

“We do believe that a clever way of developing titanium industrial market is to promote titanium as a first-choice material—convince engineering companies, addressing new markets and developing innovative products,” he said. “Such strategy could lead to a market demand increase up to 25 percent over the five coming years.”

The Department of Energy traced the history of OTEC, noting that in 1881, Jacques Arsene d’Arsonval, a French physicist, proposed tapping the thermal energy of the ocean. In 1930, Georges Claude, a student of d’Arsonval, built the first OTEC plant in Cuba, a system produced 22 kilowatts of electricity with a low-pressure turbine. The United States became involved in OTEC research in 1974 with the establishment of the Natural Energy Laboratory of Hawaii Authority.


 

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